Label printing of an optical disc has been conventionally carried out by a screen printing method or an offset printing method using a UV-curable ink. However, these printing methods require a plate-forming process for preparing engraved plates using numerous kinds of devices as a preparation process for printing. Therefore, there arises a defect that their production efficiency is low and the process is intricate.
Accordingly, as a method for shortening the period of time necessitated for the process and simplifying the printing device, thereby solving the above defect of the printing method, there have been proposed (A) an apparatus for electrifying the surface on which images are printed to the polarity opposite from the polarity of a toner by scorotron; applying a high voltage from the reverse side of a supporting member for toner images, such as a transfer drum or a transfer belt to electrify the surface to the same polarity as the toner, to easily peel off the toner from the supporting member for toner images; and applying a high voltage having a polarity opposite from the polarity of the toner from the reverse side of an object to be printed, thereby transferring the images to the object to be printed (Japanese Patent Laid-Open No. Hei 5-212857); and (B) a method for producing an optical disc comprising forming a printing film made of fine particles, such as toners on the reflection film formed by vapor depositing a metal, such as gold or aluminum on the recording surface of a disc substrate made of a resin, such as polycarbonates by means of electrophotography; and forming a protective film made of a resin such as a UV-curable resin on the printing film for protecting the printing film (Japanese Patent Laid-Open No. Hei 7-169096).
However, in the method (A) described above, since the voltage supplied to a charge supplying device must be made high, it is apprehensive that disadvantageous effects may be imparted to the disc. Moreover, there arises a defect that the electrically uniform transferring of the toner images to the surface of the optical disc is made difficult.
In addition, in the method (B) described above, since the thickness of the optical disc is usually 1 mm or so, there arises a defect that the electrically uniform transferring of the toner images to the surface of the optical disc is made difficult, nevertheless charges necessitated for the toner are supplied from the reverse of the surface for printing of the object to be printed before the formation of an antioxidation layer, which is provided for preventing the oxidation of the reflective film, on the surface of the disc substrate of the optical disc.
In view of the prior art mentioned above, objects of the present invention are to provide an optical disc to which toner images are electrically uniformly transferred by electrophotography, a method for producing the same and an apparatus for manufacturing the same.